Dyes have been incorporated into silica particles. (Ow, H.; Larson, D. R.; Srivastava, M.; Baird, B. A.; Webb, W. W.; Wiesner, U. “Bright and Stable Core-Shell Fluorescent Nanoparticles” Nano Letters 2005, 5, 113-117/Verhaegh, N. A. M.; Blaaderen, A. v. “Dispersions of Rhodamine-Labeled Silica Spheres: Synthesis, Characterization, and Fluorescence Confocal Scanning Laser Microscopy” Langmuir 1994, 10, 1427-1438./Imhof, A.; Megens, M.; Engelberts, J. J.; Lang, D. T. N. d.; Sprik, R.; Vos, W. L. “Spectroscopy of Fluorescein (FITC) Dyed Colloidal Silica Spheres” J. Phys. Chem. B 1999, 103, 1408-1415.).
Loaded latexes with IR dyes have been employed for imaging and photographic applications (for example, refer to US 2002/0113854 and U.S. Pat. No. 6,706,460). Latexes loaded with non-IR dyes are known for biological and diagnostic applications.
US 2008/0181965 describes incorporation of lipophilic versions of dyes, with examples taken largely from the class of carbocyanine dyes, such as those known in the art as Cy3, Cy5, Cy5.5, and Cy7. These dyes do not exhibit a large Stokes shift.
US 2008/0206886 describes structural modifications to the carbocyanine class of dyes which result in remarkable Stokes shifts. The described structures include polar functionality for water solubility attached to the aromatic groups and a functional group on a side chain (R5) which makes it possible to attach the dyes to various bio-molecules like antibodies and other types of proteins and peptides.
US 2005/0244976 relates to methods of detecting anionic proteins in a sample with fluorescent carbocyanine dye compounds. The reference is of use in a variety of fields including immunology, diagnostics, proteomics, molecular biology and fluorescence based assays. Anionic proteins are detected in a sample with fluorescent carbocyanine dye compounds. The reference also describes methods of simultaneously detecting anionic and non-anionic proteins in a sample with discrete fluorescent signals produced by carbocyanine dye compounds.
U.S. Pat. No. 6,964,844 relates generally to the synthesis of novel dyes and labels and methods for the detection or visualization of analytes and more specifically to fluorescent latex particles which incorporate the novel fluorescent dyes and utilize, in certain aspects, fluorescence energy transfer and intramolecular energy transfer, for the detection of analytes in immunoassays or in nucleic acid assays. These dyes are water soluble hybrid phthalocyanine derivatives useful in competitive and noncompetitive assays immunoassays, nucleic acid and assays are disclosed and claimed having (1) at least one donor subunit with a desired excitation peak; and (2) at least one acceptor subunit with a desired emission peak, wherein said derivative(s) is/are capable of intramolecular energy transfer from said donor subunit to said acceptor subunit. Such derivatives also may contain an electron transfer subunit. Axial ligands may be covalently bound to the metals contained in the water soluble hybrid phthalocyanine derivatives. Ligands, ligand analogues, polypeptides, proteins and nucleic acids can be linked to the axial ligands of the dyes to form dye conjugates useful in immunoassays and nucleic acid assays.
U.S. Pat. No. 4,997,772 relates to a core/shell polymer particle containing a detectable tracer material in the core only. It also relates to an immunoreactive reagent and the use of that reagent in analytical elements and methods. A water-insoluble polymeric particle has an inner core comprising a detectable tracer material distributed in a first polymer for which the tracer material has a high affinity. This first polymer has a glass transition temperature (Tg1) less than about 100 degree C. The particle also has an outer shell comprising a second polymer for which the tracer material has substantially less affinity relative to said first polymer. This second polymer has a glass transition temperature (Tg2) which is greater than or equal to the term [Tg1−10° C.]. It also contains groups which are either reactive with free amino or sulthydryl groups of an immunoreactive species or which can be activated for reaction with such groups. Such a species can be covalently attached to this particle to form an immunoreactive reagent which is useful in analytical elements and various analytical methods including immunological methods, for example, agglutination assays.
US 2004/0038318 relates to a reagent set and to a method, for carrying out simultaneous analyses of multiple isoenzymes in a test sample, including a bodily fluid. The reference describes measuring creatine kinase isoenzymes in particle, or bead, based multiplexed assay systems.
U.S. Pat. No. 4,891,324 relates to methods for performing an assay for determining an analyte by use of a conjugate of a member of a specific binding pair consisting of ligands and receptors, for example, antigens and antibodies, with a particle. The method has application to heterogeneous immunoassays of biological fluids, for example, serum or urine. The method is carried out using a composition that includes a conjugate of a first specific binding pair member with a particle. A luminescer is reversibly associated with a nonaqueous phase of the particle. Where the first specific binding pair member is not complementary to the analyte, a second specific binding pair member that is capable of binding to the first specific binding pair member is employed. Unbound conjugate is separated from conjugate that is bound to the analyte or to the second specific binding pair member. A reagent for enhancing the detectability of the luminescer is added and the light emission of the luminescer acted on by the reagent is measured.
WO 2006/016166 relates to polymeric materials suitable for medical materials. This reference discloses a polymer containing an alkoxyethyl acrylate monomer, a monomer containing a primary, secondary, tertiary or quaternary amine group and a monomer containing an acid group. The polymer composition forms fibers with the preferred size of 0.5 to 2.0 um, which is still not sufficient to provide nanoparticles less than 100 nm in size which are colloidally stable and can be loaded with non-water soluble fluorescent dye for the purposes of diagnostic imaging.
U.S. Pat. No. 5,326,692 relates to polymeric materials incorporating multiple fluorescent dyes to allow for controlled enhancement of the Stokes shift. In particular, the reference describes microparticles incorporating a series of two or more fluorescent compounds having overlapping excitation and emission spectra, resulting in fluorescent microparticles with a desired effective Stokes shift. The novel fluorescent microparticles are useful in applications such as the detection and analysis of biomolecules, such as DNA and RNA, that require a very high sensitivity and in flow cytometric and microscopy analytical techniques. The reference relates to microparticles incorporating a series of two or more fluorescent dyes having overlapping excitation and emission spectra allowing efficient energy transfer from the excitation wavelength of the first dye in the series, transfer through the dyes in the series and re-emitted as an optical signal at the emission wavelength of last dye in the series, resulting in a desired effective Stokes shift which is controlled through selection of appropriate dyes.
IR-emissive nanoparticulate assemblies for physiological imaging suffer from several problems. First, the dyes are often highly aggregated and hence nonemissive. Second, the fluorescence for the dye-nanoparticle assemblies is often inefficient in an aqueous environment. Third, the dyes used in such assemblies are unstable to light and oxygen and bleach readily, which makes handling and administration difficult. Fourth, such assemblies are often colloidally unstable and cytotoxic. The present invention addresses these problems by providing for loaded latexes possessing a combination of properties that make them well suited for specific biological applications. In addition to giving enhanced fluorescence efficiencies, they are highly biocompatible, are resistant to adhesion of serum proteins, and remain well dispersed over as wide range of conditions.